“Formal Features” are the camera cuts, pans, zooms, etc. used very frequently in TV and movies. Because these “formal features” are so novel, and different from normal everyday reality, they trigger the brain’s “orienting response”.
The “orienting response” is an important brain reflex that alerts us when there is a change in the environment. This “orienting response” is an essential survival mechanism because it forces us to pay attention to any (potentially dangerous) changes in the environment.